Draft gear



llg- 28, 1956 D. s. CAMPBELL 2,760,651

DRAFT GEAR Filed Sept. 5, 1952 5 Sheets-Sheet 1 ug. 28, 1956 D. s. CAMPBELL 2,760,651

DRAFT GEAR Filed Sept. 5, 1952 5 Sheets-Sheet 2 IN V EN TOR.

Aug. 28, 1956 D. s. CAMPBELL DRAFT GEAR 5 Sheets-ShamI 3 Filed Sept. 5, 1952 INVENTOR.

Aug. 28, 1956 D. s.. CAMPBELL DRAFT GEAR 5 Sheets-Sheet 4 Filed Sept. 5. 1952 Allg 28, 1955 D. s. CAMPBELL K 2,760,651

DRAFT GEAR Filed Sept. 5, 1952 5 Sheets-Sheet. 5

INVENTOR DRAFT GEAR David S. Campbell,A Glen Ellyn,l Ill.,.ass,ignor to Cardwell Westinghouse Company, a corporation of Delaware Application September 5, 1952, VSeriaINo. 308,081 4 Claims. (Cl. 213-31) This invention relates Vto draft gears for railway cars, and has for its principal object to provide afriction element in which friction shoes are applied through rubber that is subject to the force to becushioned.

It is contemplated that the force will be applied lengthwise to the car, and the rubber will move the shoes laterally With respectto the center line of the car.

1t is also contemplated that such a gear will serve as a main cushioning element in' association with an auxiliary or emergency cushioning element to assist in absorbing the shocks, and in many cases to provide an emergency capacity for excessive shocks.

Further objects and advantages of the invention will appear as the disclosure proceeds and the description is read in connection with the accompanying drawings, in which:

Fig. 1 is a vertical section through a draft gear including main and auxiliary cushioning elements embodying the invention;

Fig. 2 is a similar View showing the 'gear compressed;

Fig. 3 is a perspective view showing the. interrelation between the casings of the two cushioningelements under compression;

Fig. 4 is an end view looking from the left in Fig. 1, parts being broken away;

Fig. 5 is a perspective view of the main friction element;

Fig. 6 is a partial plan view and partial sectionr` showing the draft gear in a standard draftgear pocket associated with familiar elements including a vertical yoke;

Fig. 7 is a vertical section of'Fig. 6V along thecenter line of the car, the cushioning elements being shown solid; t

Fig. 8 is a partial plan and partial section showing the draft gear applied at one end of the car and also at the mid portion of the car between the car body and the center sill structure;

Fig. 9 is a cross-section on the line 9-9 of Fig. 8;

Fig. 10 is a perspective view of the frame or casing of the auxiliary cushioning unit;

Fig. 11 is an enlarged plan of the intermediate portion of the car showing the application of the gear between the body and the center sill structure;

Fig. 12 is a vertical section on the line 12-12 of Fig. 11; and

Fig. 13 is a cross-section on the line 13-13 of Fig. 12.

But these diagrammatic drawings and the corresponding description are used for the purpose of illustrative disclosure only, and are not intended to impose unnecessary limitations on the claims.

The main cushioning element or draft gear, generally indicated by 10, includes a tubular casing 11 having a flanged head or follower 12 provided with a hollow boss 13. Within the casing are spring elements 14 and 15 acting between the head 12 and the spring seat 16, which latter comes to rest against a shoulder 17 in a casing 11 to limit the compression of the spring elements.

The main friction element includes a tube 18 of rubnid satt-,s Patent-o 2,760,651 Patented Aug. as, rast;

ber and a series of friction shoes 19 surrounding'it and cooperating with an inner wall of the casing 11 to' provide the shock absorbing friction.

The tube 1'8 is provided with generally rectangular projections 21 which are received within recesses-or pockets 22 in the shoes 19,'which are vulcanized to the rubber of the tub-e 18.

The tube also receives a ysleeve 23 vulcanized to it.

The tube is somewhat tapered towardthe ends, and projects beyond the shoes and the sleeve 23,"as indicated at 24, for contact with the springseat 16 and a follower 25 in use. Y

When applied to a car, draft or buiiing force tends to compress the tube- 18 between the Ifollower 25 and the spring seat 16 and the spring elements 14 and 15 between the spring seat 16 and the head Hf In fact, those elements are slightly compressed when the gear is in released condition-to the end that there will be initial friction between the shoes 19 and the inner surface of the ice casing as the gear begins to close. p

The greater the force, the greater the tendency to shorten the tube 18 and to expand it, thereby increasing the pressure of the shoes 19 against the inner wall of the casing and correspondingly increasing the friction. When the spring seat 16 comes against the shoulder 17, no further compression is applied to the springY elements 14 and 15, and the tube 18 with its friction shoes 19 continues to furnish shock absorbing capacity to the limit of the gear.

The initial compression is provided by` a bolt 26 having its head in the hollow boss 13 audits threaded endvprovided with a nut 27 and a washer 28qadju'sted`v against the outer end of the sleeve 23.

The structure described mayv be used asa draft gear in a standard draftgear pocket,or variedv tol other conditions. In manyr instances, however, itis preferred to use it in association with an auxiliary cushioningek# ment sometimes serving as an ernergenc'yvto Vprovide additional cushioning when theabove'deseribedA 'structurel has fully closed. 'I j The auxiliary cushioning unit @includes-'a'f1-artrite or casing 30' having rectangular, open ilanges`31adapted to receive the innerendv of the'casingfll with the' anged' head I2' between the rectangular flanges 31.`

The cushioning elements of the auxiliary draftigear include 'plates' 32 4ot relatively"incompressible-5 material (preferably steel, S. A. E.- 1610 is satisfafctoryl provided with rows ofaligned' openings, and rubber bars or mats 33 lying over the openings at each side of the plates 32 and connected by plugs through those openings, the bars being of a rubber composition of suitable durometer hardnessfor example, 58 to 62.

interposed between the resilient units is a spacing plate.

The details of construction of the auxiliary cushioning unit may be substantially as disclosed in the application of Herbert E. Tucker, Ser. No. 272,817, filed February 21, 1952.

The cushioning elements are compressed between the end of the frame 30 and the follower 20, and held in pre-compressed condition by keys 34, which are really rectangular bars corresponding to the thickness of the flanges 31 and inserted between those flanges and the follower 20.

The capacity of the auxiliary or emergency cushioning unit may be made to suit conditions or preferences, and when it is used as an emergency it will have a capacity that will provide safety or emergency cushioning when the associated main draft gear has gone solid.

The main cushioning unit may be used as a draft gear in a vstandard pocket in association with familiar parts shown in Figs. 6 and 7, and of which 36 indicates the center sills, 37 the draft lugs, 38 the vertical yoke, 39 the coupler, and 40 the key.

In a similar relation, thel main auxiliary cushioning units may be used at the ends of the car and proportioned so as yto t within the standard draft gear pocket or in a special draft gear pocket. f v

For some uses, it is also desirable to provide cushioning between the center sill structure of the car and its body, in which case the draft gear arrangement such as shown in Figs. 6 and 7 may be supplemented, as shown in Figs. 8-13, byra draft gear assembly generally indicatedl by 41 between the Vcenter sills 36 and the boxlike frame generally indicated by 51 on the car body through which the center sill structure may' move lengthwise in opposite directions subject to the cushioning of the draft gear. The frame 51 is here shown in Fig. 9 as including spaced upper and lower elements 42 and side elements 43, and there are vertical cross pieces 44, which include upright faces 45 adapted to cooperate with followers 46 at opposite ends of the draft gear.

The draft gears at the end of the car may be designed to give the standard travel of 2%" to 25/8", whereas the draft gear in the middle of the car may be designed to give up to 7 of travel between the car body and the center frame structure connected with the couplers to form what may be called a train line. p Y

An outstanding and desirable characteristic of the main cushioning element is that the rubber tube 18, in addition to its resilience in absorbing shock and prompting release, acts as a lluid in transmitting pressure uniformly to the friction shoes 19. It appears to be a fluent vehicle for receiving, transmitting, and distributing the force of the buing and draft shocks.

Friction may be relied upon for at least 85% of the energy absorption in buff and draft, and to control rebound during release.

The main cushioning element may Well be designed to take normal buing shocks and the auxiliary cushioning e element designed to provide emergency absorption for fast switching shocks.

Metal parts are satisfactory in steel. The'housing and friction shoes are preferably heat treated.

For some applications, the main cushioning element a rubbervtube, a sleeve within the tube, andk friction shoes around the tube in contact with the casing said tube pressing against substantially the entire inner surface of said friction shoes and projecting beyond the ends of the sleeve and shoes so that a compressive force applied to a projecting end of said tube will substantially simultaneously tend to cause the body thereof to expand outwardly and urge said friction shoes into tighter engagement with the wall of said casing. i

2. In a draft gear for railway cars, a hollow casing, a spring in the/casing, a spring seat against the spring and a friction element against the spring seat including a rubber tube, a sleeve'within the tube, friction shoes around the tubein contact with the casing said tube pressing against substantially the entire inner surface of said friction shoes and projecting beyond the ends of the sleeve and shoes so that a compressive force applied to a projecting end of said tube will substantially simultaneously tend to cause the body thereof to expand outwardly and urge said yfriction shoes into tighter engagement with Athe wall of said casing, and an auxiliary cushioning element against which the casing acts. i

3. In a d-evice of the class described, a hollow casing having a movable spring seat therein, a spring in the casing on one side of the movable seat and having one end seated thereagainst,. xed means for seating the opposite end of the spring, a rubber tube in the casing on the side of the movable seat opposite said spring, friction shoes secured around the outside of said tube and frictionally engagingvthe inner wall of thecasing, one end of said tube engaging-said movable seat and the opposite end thereof projecting from the end of the casing, whereby a compression force applied to the projecting end .of said tube will tend to cause the body thereof to expand outwardly and urge said friction shoes into tighter engagement with the wall of said casing.

4. A deviceof the characterset forth in claim 3 including a sleeve secured in said tube, and means passing through said sleeve for securingsaid tube, seat and spring in assembled relation in said casing.

References Cited in the le of this patent UNITED srATEs PATENTS 2,245,296 Piron g June l0, 1941 2,263,599 Tucker Nov. 25, 1941 2,277,881 Olander Mar. 31, 1942 2,390,496 Campbell Dec. 11, 1945 2,409,500 Krotz Oct. 15,' 1946 2,451,569 Lounsbury Oct. 19, 1948 2,650,721 Bourdon 1 Sept. l,- 1953 

